Effect of temperature, pH and culture media on the growth and lactic acid production of Lactobacillus acidophillus CRL 1259

MARÍA SILVINA JUÁREZ TOMÁS; BIRGITT WIESE; MARÍA ELENA NADER-MACÍAS

Roma. Italia.

Congreso; 2º Probiotics, Prebiotics & New Foods; 2003

Idea Congress Srl

Objetive. To study the effect of temperature (30, 37 and 45ºC) pH (5, 6.5 and 8) and culture media (MRS or LAPTg broths) on the growth and lactic acid production by Lactobacillus acidophilus CRL 1259 isolated from human vagina. This microorganism was previously selected by its capability to inhibit the growth of different uropathogenic microorganisms. Methods. The growth of L. acidophilus was determined spectrophotometrically (540nm) and by viable counts. The production of lactic acid was analyzed by the pH decrease and by the Lactic dehydrogenase test. The results were evaluated by the Gompertz and nonlinear mixed-effects models. The statistical programs SAS 8.2, SPSS 10 and S-Plus 2000 were used. Results. The optimal conditions both for the growth and lactic acid production by L. acidophilus were: pH of 6.5 or 8.0, and temperature of 37ºC. The growth was higher in LAPTg than in MRS. However, the lactic acid production was more efficient in MRS. The initial pH of the culture medium and the temperature of incubation exerted significant effects on all the growth parameters (increase of biomass, growth rate and lag phase). However, the culture medium used only affected significantly the final biomass. Conclusions. The application of the Gompertz model and the statistical software help to determine in a very fast way the effect of different factors on the growth and lactic acid production by L. acidophilus CRL 1259. The results obtained in lab experiments allow considering the inclusion of L. acidophilus CRL 1259 in a probiotic product for vaginal application.